Human Health and Ecological Risk Assessment

for the Use of Wildlife Damage Management Methods

by APHIS-Wildlife Services

Chapter XXVIII

THE USE OF NONCHEMICAL DETERRENTS IN WILDLIFE 

DAMAGE MANAGEMENT

Draft

March 2024
i

EXECUTIVE SUMMARY

Nonchemical deterrents are devices or tools (e.g., vehicles, remote control vehicles, effigies, 

lights, propane cannons) United States Department of Agriculture (USDA), Animal and Plant 

Health Inspection Service (APHIS), Wildlife Services (WS) uses for wildlife dispersal in damage 

management projects. Wildlife dispersed by WS using nonchemical deterrents during the analysis 

period (Federal fiscal years 2016-2020) involved birds (99% of the wildlife dispersed) and 

mammals and reptiles (1%). Most of the projects conducted by WS were to prevent wildlife 

hazards at airports and to protect natural resources (including threatened and endangered

species), agricultural crops, and livestock. WS uses several nonchemical deterrents to disperse

wildlife through physical, visual, or auditory means. These devices include rubber ammunition,

remote-controlled vehicles, lights, effigies, mylar and non-mylar flagging, propane cannons, and 

electronic harassment. Propane cannons and vehicles were the most commonly used 

nonchemical deterrents, accounting for 80% of all wildlife dispersed.

APHIS evaluated the potential human health and environmental risks from WS's proposed use of 

nonchemical deterrents and determined that the risks to human health and the environment are 

negligible. Risks to workers are low because WS personnel are trained in the proper use and 

setup of nonchemical deterrents. Risks to the general population are negligible because site 

selection and timing of activities minimize exposure to the public. Nonchemical deterrents would 

not contaminate water or result in the bioaccumulation of chemicals or other hazardous materials. 

Environmental hazards associated with nonchemical deterrents are generally limited to 

unintentional disturbances of nontarget animals that may be near a targeted animal.
ii

Table of Contents

1 INTRODUCTION ................................................................................................................ 1

1.1 Nonchemical Deterrents............................................................................................... 1

1.1.1 Physical ................................................................................................................ 1

1.1.2 Visual.................................................................................................................... 2

1.1.3 Auditory ................................................................................................................ 5

1.2 Use Pattern of Nonchemical Deterrents....................................................................... 7

1.2.1 Visual.................................................................................................................... 7

1.2.1 Auditory ................................................................................................................ 3

2 HAZARDS........................................................................................................................... 6

2.1 Human Health and Safety Hazards................................................................................... 6

2.1.1 Visual.................................................................................................................... 7

2.1.2 Auditory ................................................................................................................ 7

2.2 Environmental Hazards................................................................................................ 8

3 RISKS................................................................................................................................. 8

3.1 Human Health and Safety Risks .................................................................................. 8

3.1.1 Visual.................................................................................................................... 9

3.1.2 Auditory ................................................................................................................ 9

3.2 Environmental Risks .................................................................................................... 9

4 UNCERTAINTIES AND CUMULATIVE EFFECTS.............................................................10

5 SUMMARY ........................................................................................................................10

6 LITERATURE CITED.........................................................................................................11

7 PREPARERS.....................................................................................................................15

7.1 APHIS WS Methods Risk Assessment Committee......................................................15

7.2 Internal Reviewers ......................................................................................................16

APPENDIX 1. "Other Species" Included in Tables ....................................................................18
1

1 INTRODUCTION

The U.S.Department of Agriculture, Animal and Plant Health Inspection Service (APHIS), Wildlife 

Services (WS) uses nonchemical wildlife damage management (WDM) methods to deter or 

disperse animals that cause damage primarily to agricultural and natural resources and property 

and pose hazards to human health and safety (e.g., airports). Deterrent techniques can be a 

crucial component of wildlife hazard management plans because the deterred target species will 

return as long as the attractant is accessible. Consistent use of nonchemical deterrents, especially 

through the use of various methods, can result in more successful deterrence (i.e., the animal 

chooses not to return to the site or perform the behavior even when the deterrent is not being 

applied). Target species in nonchemical deterrent WDM include avian species, such as vultures, 

gulls, geese, and blackbirds, and mammal species, such as deer, black bears, coyotes, and 

wolves.

WS uses several nonchemical deterrents designed to make the area or resource unattractive to

wildlife or create uncomfortable or fearful conditions for wildlife through physical, visual, or 

auditory devices. During FY16-20, these devices included rubber ammunition, paintballs, 

vehicles, remote-controlled vehicles, lights, effigies, mylar and non-mylar flagging, propane 

cannons (gas exploders), and electronic harassment. Propane cannons and vehicles were the 

primary nonchemical deterrents, accounting for 80% of all wildlife dispersed. Wildlife damage 

management activities occurred at airports for the protection of human health and safety, in 

agricultural settings for the protection of crops such as sunflowers and apples, and livestock such 

as backyard flocks of chickens and turkeys, calves, goats, and sheep, and for the protection of 

natural resources including endangered species such as salmon, and property such as backyard 

gardens and landscaping. Birds were the primary target of nonchemical deterrents, resulting in 

99% of the wildlife dispersed. Mammals were also involved in dispersal projects, with 1% 

dispersed.

This human health and ecological risk assessment provides a qualitative evaluation of the 

potential risks and hazards to human health, wildlife, and the environment due to using 

nonchemical deterrents to deter wildlife in targeted areas. The methods used in this risk 

assessment follow standard regulatory guidance and methodologies and generally conform to 

other Federal agencies such as the US Environmental Protection Agency (EPA) (National 

Research Council 1983, USEPA 2022). 

1.1 Nonchemical Deterrents

Nonchemical deterrents use animal behavior modification to deter or repel damaging animals, 

thereby reducing damage to the protected resource. Effective nonchemical deterrents must affect 

some aspect of the intended target animals' physical receptors or psychological perception. The 

primary physical receptors in target species are physical, visual, and auditory (Seamans et al. 

2013). Various nonchemical deterrents are used alone or in combination depending upon the 

species targeted and its habits.

WS also uses lasers, unmanned aerial vehicles (UAVs), unmanned aircraft systems (UASs), or 

drones to haze wildlife. These two deterrents have unique risks and regulations associated with 

them. Thus, these two deterrents will be discussed in separate risk assessments.

1.1.1 Physical
2 

Physical deterrents include barriers (e.g., spikes or wires) and projectiles (e.g., rubber bullets, 

paintballs). These devices create painful or uncomfortable stimuli to repel the target animal 

(Seamans et al. 2013) by causing physical pain, discomfort, or hazing via continuous harassment

using a scare tactic (Preusser et al. 2008). This section provides some examples of physical 

deterrents that WS may use. The risks associated with these deterrents are covered in The Use 

of Firearms in Wildlife Damage Management (USDA Wildlife Services 2019), and the Use of 

Exclusion in Wildlife Damage Management (USDA Wildlife Services 2023b) and will not be 

discussed further in this document.

Anti-perching Devices and Overhead Wires- Antiperching devices are sold under trade names such 

as Nixalite® or Cat Claw® and can be used to 

exclude birds, including gulls and starlings, from 

ledges, railings, and other roosting or loafing 

surfaces (Homan et al. 2017, Lowney et al. 2018, 

Williams and Corrigan 1994)(Figure 1).

Overhead wires of steel or monofilament are used to 

deter birds from landing on ledges, rooflines, or 

lakes. The wire is constructed in parallel lines over 

the site to be protected. It is important to consider the species of bird that is the target animal to 

ensure that wire spacing effectively eliminates access for birds into restricted areas. Wire has 

become an effective tool in eliminating the access of gulls and other birds from sites (Solman 

1994).

Beanbags- The 12-gauge bean bag is a shotgun round that discharges a 2.5 cm (1 in) fabric bag 

filled with lead shot with a muzzle velocity of about 90 m (300 ft)/sec. Caution should be exercised, 

as penetration or injury can occur if discharged at a distance of less than 10 m (30 ft) from the 

target, but individual product specifications should be followed. The maximum effective range is 

usually 25 m (85 ft), within which the accuracy is generally reliable. If a physical deterrent seems 

warranted, bean bags are recommended over rubber slugs, as the chance of injuring an animal 

or bystanders is lower. Beanbag rounds may be used to form an aversion to a behavior (Shivik 

2006). However, this method must be used consistently so the animal does not identify conditions 

when it can obtain a resource without receiving the negative stimulus (Shivik 2004). 

Rubber Ammunition- The 12-gauge rubber slug is a shotgun round that discharges a 73-grain 

rubber baton with a muzzle velocity of 220 m (738 ft)/sec. Caution should be exercised, as 

penetration or injury can occur if discharged at a distance of less than 25 m (85 ft). The 

recommended range is 30-50 m (98-164 ft). Compared to 12-gauge beanbags, the higher muzzle 

velocity of rubber ammunition creates a higher potential for injury to an animal or bystander; 

however, the effective range is much greater. As with beanbags, deterrence with rubber 

ammunition must be used consistently so the animal does not identify conditions when it can 

obtain a resource without receiving the negative stimulus (Shivik 2004). 

1.1.2 Visual 

Visual deterrents, such as motorized vehicles, remote control vehicles, vulture and human effigies 

or silhouettes, eye-spot balloons, flags, and mylar reflecting tapes, have shown only short-term 

effectiveness and are inappropriate as long-term solutions to wildlife damage. Most short-term 

success achieved with these devices is likely attributable to "new object reaction" rather than any 

actual repellent effect they produced (Cleary and Dolbeer 2005). A disadvantage is that animals 

Figure 1. Porcupine wire installed at an 

airport to prevent perching birds (e.g., 

raptors).
3 

often quickly become accustomed to these devices, known as habituation, and, in time, ignore 

them. When combined with other methods, the effectiveness of visual deterrents can be 

prolonged. Visual deterrents also have more success if they are moved to different locations

periodically. This section provides some examples of visual deterrents that WS may use.

Motorized Vehicles- Vehicles can be an effective hazing tool. Vehicles are more effective in 

rural rather than urban areas because animals can behave unpredictably, and hazing may cause 

animals to move, where they could create the same or different hazards. WS can use vehicles to 

haze wildlife on airfields. For example, vehicles may be used to scare wildlife loafing on runways 

prior to an aircraft taking flight or landing. Vehicles can include trucks, cars, boats, all-terrain 

vehicles (ATVs), electric bikes, and motorcycles. WS, for the most part, uses trucks, boats, and 

ATVs. While most of the stimulus is the visual aspect of the vehicle, noise from the engine or car 

horn adds an auditory feature as well.

Remote Controlled Vehicles- Animals can be dispersed from areas where they cause damage 

or threats by being pursued with remote control vehicles (e.g., boats and cars). Remote control 

vehicles are often used with physical human harassment (e.g., people pursuing animals on foot, 

clapping their hands, or shouting) and non-motorized or motorized boats. Consistent use of 

deterrents can result in keeping animals away from an area. Curtis et al. (2016) found the 

combined use of remote-controlled vehicles with pyrotechnics effective for hazing Canada geese 

out of city parks. Additionally, Breck et al. (2023) found that combining a remote controlled vehicle

with a commercially available predator deterrent doubled the efficacy of the predator deterrent 

alone on a colony of captive coyotes.

Flashing Lights- Lighting devices can be deployed to deter animals from using certain areas.

LED lights in the device flash irregularly, replicating human presence to increase an animal's 

sense of perceived risk. WS uses flashing lights primarily to deter predators from attacking 

susceptible livestock. These devices were initially developed to protect livestock from foxes in

Australia. Flashing lights have been adopted in the United States to protect sheep from predators 

at night by simulating human activity (Stone et al. 2017).

Effigies- Effigies, scarecrows, or representations 

of target species, such as vultures and predators 

such as eagles and coyotes, are effective 

components of integrated management 

strategies (Avery et al. 2002, Avery et al. 2008, 

Seamans 2004, Tillman et al. 2002). Target 

species effigies include carcasses, taxidermied 

mounts, and artificial models used to represent 

dead animals. For example, hanging effigies of 

vultures in the "death pose" from structures such 

as towers, bridges, and other structures tend to 

disperse vultures quickly from loafing and 

roosting sites (Figure 2). Bird effigies are typically 

displayed in a prominent location so birds using 

the roost will notice them. The effigy is hung 

upside down by its feet, far enough from 

branches or other contact points to prevent

entanglement. A modified bow and arrow rig is often used to launch the line over a branch and 

suspend effigies at a tree roost. Using the feathers of the target species in the effigy seems to be 

important in their success. A permit is required to possess and use a dead or preserved bird or 

Figure 2. Example of effigies, vulture (Left) and 

gull (Right) to disperse birds from loafing and 

roosting sites.
4 

its feathers. These effigies are most effective for conspecific species roost dispersal but may also 

be effective for other flocking birds. Vulture and crow effigies can effectively resolve various 

problems associated with roosting vultures and crows, including property damage at 

communication towers, depredation of crops and livestock, and aircraft safety (Avery et al. 2008). 

Predator effigies, such as human, coyote, and eagle effigies, are typically located where birds 

enter a field up to the center or other areas to prevent target bird use. Predator effigies should be 

frequently moved so birds do not habituate to them.

Tape/Flags- Reflective ribbons, such as mylar

and non-mylar tape and flags, are sometimes 

used to deter birds. The reflecting tape, which is 

evaluated most often in field tests, is 

approximately 1.0 cm wide and 0.25 mm thick. 

The tape is usually twisted and suspended 

between erect poles in parallel lines above the 

crop. Its mylar coating (silver on one side, red on 

the other) reflects sunlight, which produces a 

flashing effect. Twisting the tape enhances the 

reflecting effect and creates an illusion of motion 

(Figure 3). In windy conditions, vibrations made

by the tape produce a humming or roaring noise, 

which may contribute to its deterrent effect 

(Bruggers et al. 1986, Dolbeer et al. 1986, Tobin 

et al. 1988). The effectiveness of mylar ribbon is variable. Mylar ribbon protected corn, millet, 

sunflower, and sorghum fields from bird damage (Bruggers et al. 1986, Dolbeer et al. 1986). 

For goose management, a more cost-effective flag made of white or black plastic can be effective. 

Flags are made of white garbage bags (30 x 60 in; 77 x 154 cm) stapled widthwise to a four-foot 

(1.2 m) length wooden lath and placed at a density of one flag per acre. White or black flags 

offered significant protection from snow goose grazing in agricultural fields (Mason et al. 1993, 

Mason and Clark 1994). 

Fladry1

- Fladry is a barrier device explicitly used 

for predators, such as coyotes and wolves. Fladry 

may alleviate livestock predation by taking 

advantage of wolf and coyote fear of unfamiliar 

items on the landscape (Windell et al. 2021, Young 

et al. 2019). Fladry consists of a continuous rope 

strand with strips of red or orange flagging (20 x 4 

in; 50 x 10 cm) sewn or tied at 20 in (50 cm) 

intervals and strung 20 in (50 cm) from the ground 

for wolves (Musiani et al. 2003) (Figure 4). Closer 

spacing of fladry has been shown to be more 

effective with coyotes (11 in, 28 cm) (Young et al. 

2019). Turbo fladry is modified from typical fladry by 

carrying an electric charge along the rope—recent 

testing conducted by WS using turbo fladry to protect crops from feral swine damage has shown 

1 Risks associated with fladry are covered in “The Use of Exclusion in Wildlife Damage Management” Risk 

Assessment (USDA Wildlife Services 2022) and will not be covered in this risk assessment.

Figure 3. Mylar tape strung across a field to 

deter depredating birds.

Figure 4. Fladry installed on cow pasture 

fence to alleviate predation by coyotes.
5 

positive results (Unpublished data 2022). Fladry can protect prairie dog colonies, black-footed 

ferrets, and livestock, especially during critical seasons (e.g., calving) (Windell et al. 2021). 

Balloons- Weatherproof, vinyl, inflatable balloons 

with large eyes or "eye spots" can be used to deter

pest birds. Holographic eyes are especially helpful in 

creating an illusion that the eyes follow the birds like 

a predator ready to attack. The "eye" movement 

combined with the balloon's natural movement in the 

wind reduces the likelihood that birds will become 

accustomed to the product (Figure 5). Balloons can 

be suspended from poles so that they swing freely in 

the wind, or they can be inflated with helium and 

tethered to float above the area to be protected. 

Some efficacy has been shown in reducing blackbird 

numbers at roosts (Mott 1985) using helium-filled 

balloons of various colors. Helium balloons are used 

for roosts and floated up and over the roosting trees; 

fishing lines with a swivel attached to the balloon are 

effective for letting balloons out and retrieving them so 

they can be used for multiple days. They have also 

been used for geese at a density of 3 to 5 balloons per 

acre but must be put in place before they acclimate to 

the site (French and Parkhurst 2009). Although 

effective in the short term, the efficacy of balloons or 

eye spots decreases over time as the birds habituate 

to them (McLennan et al. 1995). 

Inflatable Deterrents- Inflatable scarecrow or human 

shaped deterrents are sold under trade names such 

as “Scarey Man”, “Air Dancer”, or “Scare Dancer” 

(Figure 6). These devices rapidly inflate and move 

unpredictabilly. They can be used to deter birds, 

including pigeons and starlings, from ledges, railings, 

and other roosting or loafing surfaces in fruit crops 

(Steensma et al. 2016), or in hazardous places (Snow 

et al. 2021). WS has used these devices to disperse 

starlings at refineries and ethanol plants. 

1.1.3 Auditory

Auditory deterrents, such as pyrotechnics, propane cannons, and various electronic distress 

devices, alter the behavior of birds and mammals using sound. These devices produce sounds 

similar to shotguns, distress calls of birds, or other noises that are perceived by animals as 

dangerous. They are often used in conjunction with visual deterrents. This section provides some 

examples of auditory deterrents that WS may use. The risks associated with pyrotechnics are 

covered in The Use of Explosives in Wildlife Damage Management (USDA Wildlife Services 

2023a). 

Figure 5. Eye spot balloon used to disperse 

flocking birds (e.g., geese, gulls).

Figure 6. Air dancer installed at a facility 

to deter flocking birds.
6

Propane Cannons- Propane cannons generate 

a shotgun-sounding blast. Propane cannons are 

commonly used to disperse blackbirds, waterfowl, 

and other birds from agricultural crops, 

wastewater ponds, and airfields (Figure 7). These 

devices produce loud (120-decibel [dB]) 

intermittent explosions at 1- to 30-minute intervals 

and are effective in areas up to 120 acres with a 

recommendation of one cannon per 4-6 acres 

(Avery and Werner 2017, Cummings et al. 1986). 

Recent research suggests placing one cannon 

every 1,000 ft (300 m) for maximum effectiveness 

with red-winged blackbirds and brown-headed 

cowbirds (Duttenhefner and Klug 2024) Newer 

versions emit up to three explosions in rapid 

succession and various directions. Birds quickly 

habituate to cannons that detonate at systematic 

or random intervals throughout the day. Thus, it is best to use cannons sparingly and only when 

target birds are in the damage prevention area to ensure they remain effective. Additionally, as 

with other devices, frequently moving them enhances the duration of their effectiveness. 

Reinforcement by occasional lethal removal with a shotgun might also enhance effectiveness

(under appropriate permits).

The advantages of propane cannons are that they do not require a constant human presence, 

are relatively portable, effective day or night, and are inexpensive to operate. Disadvantages are 

that they must be moved every 2 to 3 days to prevent habituation, regular maintenance is required, 

and the noise may be a nuisance to nearby residents (Klug et al. 2023).

Electronic Distress Signals- Auditory electronic deterrents are marketed as either ultrasonic, 

sonic, or bioacoustic calls (Seamans et al. 2013). Examples of sonic calls are human-made 

sounds that are thought to frighten birds by relying on their perception of danger. Ultrasonic calls 

are those above 20 kilohertz and cannot be heard by humans or birds (Jenni-Eiermann et al. 

2014). Recent testing of directional sonic calls has been shown to disrupt starling foraging by 

overlapping the frequency with which starlings communicate (Mahjoub et al. 2015). Birds can

habituate to and ignore recorded distress calls (bioacoustic calls) and other noises produced by 

electronic auditory devices. Distress calls are more effective when there are actual threats in the 

environment. Some research has shown that conspecific distress calls are effective with reduced 

habituation compared to sonic calls (Lecker et al. 2015, Spanier 1980). Such devices can be 

helpful if used as part of an integrated program of bird dispersal (Cleary and Dolbeer 2005).

Figure 7. Propane cannon installed on an 

airport greenbelt to deter birds.
7

Recorded distress calls are available for common birds at airports, such as gulls, crows, and 

starlings. Conspecific calls broadcast from speakers mounted on a vehicle will often initially draw 

the birds toward the sound source to investigate the threat. The birds can then be dispersed using

pyrotechnics or a shotgun to remove an occasional bird. As with propane cannons, distress calls 

routinely broadcast from stationary speakers, with no associated follow-up stimuli that provide 

additional fear or stress, have little utility (Klug et al. 2023). Reinforcement by occasional lethal 

removal with a shotgun generally enhances their

effectiveness (under appropriate permits).

Scare Radios- The scare radios are a type of 

electronic deterrent device. The units are 

programmed to play FM radio (e.g., local talk shows)

during designated times, typically from dusk to dawn,

to deter predators from livestock. The scare radios are 

powered by a 12-volt deep cycle battery connected to 

a solar panel to minimize battery loss. Scare radios 

are typically positioned where predator disturbance 

has been recorded or is expected. The device can be 

mounted to trees or as a mobile unit allowing it to be 

moved whenever cattle are relocated easily (Figure 

8). The audio deterrent can be used with Fox lights or 

other visual deterrents.

1.2 Use Pattern of Nonchemical Deterrents

WS annually averaged 32,693 work tasks2 associated with nonchemical deterrents from FY16-

20. Of these work tasks, 93% were for visual deterrents (vehicles, effigies, lights, mylar tape, and 

flagging), and 7% for auditory deterrents (propane cannons and electronic harassment). It should 

be noted that all birds, mammals, and reptiles dispersed may not necessarily be documented and 

may not be estimated if WS staff were not present at the time of dispersal.

1.2.1 Visual

WS used visual deterrents, including vehicles, remote control vehicles, effigies, lights, and flags,

to disperse an annual average of 1.6 million target birds, mammals, and reptiles (Tables 1-4). WS 

used remote control vehicles and vehicles to disperse wildlife from airfields, landfills and other 

locations.

Table 1. The annual average number of target mammals and birds hazed with vehicles by WS in 

wildlife damage management activities from FY16-20 throughout the United States. Species that 

averaged less than 100 hazed annually are included in “other" categories. 

Species Dispersed

European Starling 189,045

Yellow-headed Blackbird 482

Red-winged Blackbird 15,286

Tricolored Blackbird 1,431

Brown-headed Cowbird 14,797

2 A Work Task is defined as a visit to a property, or a portion of it, where a WS employee conducts field 

work. However, duration is not considered and, thus, a Work Task could be 10 minutes to 10 hours in 

duration.

Species Dispersed

Brewer’s Blackbird 2,810

Common Grackle 5,078

Boat-tailed Grackle 724

Great-tailed Grackle 4,202

Mixed Blackbirds 5,575

Figure 8. Mobile scare radio electronic 

deterrent device for wolf damage 

management.
2

Species Dispersed

Rock Dove* 41,575

Island Collared-Dove* 1,895

Eurasian Collared-Dove* 1,112

Spotted Dove* 20,019

Zebra Dove* 49,711

White-winged Dove 1,883

Mourning Dove 65,998

Other Dove (2 sp.) 1 65

Red-legged Kittiwake 17,082

Bonaparte’s Gull 463

Laughing Gull 4,886

Franklin’s Gull 3,056

Short-billed Gull 309

Ring-billed Gull 9,402

Western Gull 482

California Gull 5,296

Herring Gull 27,572

Glaucous-winged Gull 4,040

Great Black-backed Gull 1,086

Caspian Tern 858

Whiskered Tern 348

Forster’s Tern 202

Other Larid (17 sp.)1 392

Black-bellied Whistling Duck 256

Snow Goose 28,915

Greater White-fronted Goose 4,685

Brant 2,855

Cackling Goose 37,267

Canada Goose 203,538

Hawaiian GooseT&E 4,083

Mute Swan* 141

Tundra Swan 150

Wood Duck 462

Blue-winged Teal 1,715

Cinnamon Teal 448

Northern Shoveler 9,128

Gadwall 1,310

American Wigeon 5,060

Hawaiian DuckT&E 527

Mallard (incl. domestic*) 25,636

American Black Duck 454

Northern Pintail 3,071

Green-winged Teal 2,588

Canvasback 400

Redhead 509

Ring-necked Duck 433

Greater Scaup 1,257

Lesser Scaup 1,074

Bufflehead 2,974

Common Goldeneye 718

Barrow’s Goldeneye 597

Hooded Merganser 1,145

Species Dispersed

Common Merganser 678

Ruddy Duck 750

Other Waterfowl (13 sp.) 1 411

Black-billed Magpie 1,092

American Crow 21,676

Fish Crow 629

Common Raven 26,525

Other Corvid (6 sp.) 1 112

Black Vulture 933

Turkey Vulture 3,195

Osprey 992

White-tailed Kite 226

Northern Harrier 1,910

Cooper's Hawk 220

Bald Eagle 4,817

Mississippi Kite 232

Red-shouldered Hawk 132

Swainson’s Hawk 552

Red-tailed Hawk 9,481

Rough-legged Hawk 178

Ferruginous Hawk 195

Barn Owl 306

Short-eared Owl 493

Crested Caracara 153

American Kestrel 5,096

Peregrine Falcon 114

Other Raptor (21 sp.) 1 510

Laysan Albatross 1,334

Double-crested Cormorant 26,152

American White Pelican 5,611

Brown Pelican 520

Other Waterbird (16 sp.) 1 207

American Coot 3,244

Sandhill Crane 1,741

Yellow Bittern 2,523

Great Blue Heron 2,929

Great Egret 2,069

Snowy Egret 2,036

Little Blue Heron 142

Western Cattle Egret^ 27,462

Black-crowned Night-Heron 664

White Ibis 834

Glossy Ibis 311

White-faced Ibis 991

Other Wading Bird (10 sp.)1 130

Black-necked Stilt 916

- Hawaiian Black-necked Stilt 771

American Avocet 241

Black-bellied Plover 1,233

American Golden Plover 222

Pacific Golden Plover 112,112

Killdeer 14,426
3

Species Dispersed

Semipalmated Plover 1,223

Upland Sandpiper 517

Whimbrel 612

Long-billed Curlew 1,623

Ruddy Turnstone 7,067

Sanderling 799

Dunlin 4,367

Least Sandpiper 6,328

Semipalmated Sandpiper 109

Western Sandpiper 1,703

Long-billed Dowitcher 142

Wilson’s Snipe 188

Lesser Yellowlegs 184

Willet 389

Greater Yellowlegs 207

Wood Sandpiper 104

Other Shorebird (22 sp.)1 489

California Quail^ 234

Wild Turkey 2,445

Sharp-tailed Grouse 637

Ring-necked Pheasant* 757

Gray Francolin* 4,663

Black Francolin* 2,282

Feral Domestic Chicken* 2,725

Erckel’s Francolin* 176

Other Gallinaceous (10 sp.) 1 161

Bank Swallow 2,065

Tree Swallow 2,312

Purple Martin 212

Barn Swallow 14,230

Cliff Swallow 6,583

Cave Swallow 1,435

Other Aerialists (6 sp.) 1 189

Northern Flicker 170

Rose-ringed Parakeet* 1,511

Other Non-Passerines (8 sp.)1 105

Western Kingbird 1,736

Eastern Kingbird 298

Scissor-tailed Flycatcher 952

American Pipit 1,131

Horned Lark 17,333

Lapland Longspur 360

Snow Bunting 950

Lark Sparrow 183

Lark Bunting 466

Field Sparrow 179

Fox Sparrow 187

Dark-eyed Junco 272

White-crowned Sparrow 100

Savannah Sparrow 2,329

Song Sparrow 179

Species Dispersed

Eastern Meadowlark 21,635

Western Meadowlark^ 14,165

Other Grassland Pass.(13 sp.)1 382

Bohemian Wawing 696

Northern Mockingbird 1,966

Eastern Bluebird 126

Mountain Bluebird 376

American Robin 4,783

House Finch^ 28,304

Pine Siskin 149

American Goldfinc 326

Northern Cardinal^ 1,208

Other Forest Passerine (19 sp.) 1 306

Black Drongo* 194

Eurasian Skylark* 17,297

Red-vented Bulbul* 3,259

Common Myna* 89,522

African Silverbill* 888

Java Sparrow* 3,674

Scaly-breasted Munia* 34,173

Chestnut Munia* 53,413

Red Avadavat* 2,172

Common Waxbill* 6,509

House Sparrow* 9,939

Eurasian Tree Sparrow* 836

Red-crested Cardinal* 8,641

Saffron Finch* 1,044

Other Invasive Passer.(2 sp) 1 40

TOTAL BIRDS (341 sp) 1,530,615

Coyote^ 719

Red Fox^ 408

Feral/Free-roaming Cat* 267

Black Bear 100

Other Predator (17 sp.)1 307

Black-tailed Jackrabbit 322

Desert Cottontail 294

Eastern Cottontail^ 272

California Ground Squirrel 219

Other Rabbit/ Rodent (16 sp.)1 199

White-tailed Deer^ 1,003

Mule Deer 120

Axis Deer* 646

Moose 233

Other Mammal (9 sp.)1 158

TOTAL MAMMALS (54 sp.) 5,267

Reptile (4 sp.) 1 11

TOTAL REPTILE (4 sp) 11 1Other species are listed in Appendix 1.

*Introduced species

^ Introduced populations exist
1

WS used remote control vehicles to haze birds along with a few mammals. Remote control boats 

are often used to haze waterfowl off ponds. Remote control vehicles were used mostly to disperse 

waterbird species (98.5%), primarily Canada geese (93%) from FY16-FY20.

Table 2. The annual average number of remote-controlled vehicles (e.g., boats, trucks) used to 

haze target species by WS in Wildlife Damage Management activities from FY16-20 throughout 

the United States.

Species Number Used Number Work Tasks Number Dispersed

Canada Goose 656 627 14,780

Mallard 8 8 270

Hawaiian GooseT&E 5 5 29

American Wigeon 4 4 210

Other Waterbird (11 sp.)

1 15 11 444

Passerine (2 sp.)

1 1 1 206

Raptor (2 sp.)

1 0.6 2 20

Mammal (2 sp.)

2 0.6 0.6 9

TOTAL 690 659 15,968 1,2Other species are listed in Appendix 1.

Effigies were used by WS for the protection of livestock (e.g., vulture dispersal) and human health 

and safety (e.g., gull dispersal). Species dispersed using coyote, crow, eagle, gull, human, and

vulture effigies are described in Table 3. 

In some cases, WS may provide supplies or materials of limited availability for use by private 

entities. Effigies were loaned to cooperators to disperse Canada geese, gull species, and vultures 

(Table 3).

Table 3. The annual average number of effigies used to haze target species or loaned to 

cooperators by WS in Wildlife Damage Management activities from FY16-20 throughout the 

United States.

Effigy 

Type

Species Number 

Used

Number 

Work 

Tasks

Number 

Dispersed

Number 

Loaned

Number 

Work 

Tasks

Coyote White-tailed deer 0 0 - 0.2 0.2

Coyote Feral/Free-ranging Cat 0.2 0.2 - 0 0

Coyote Double-crested Cormorant 0.6 0.6 - 0 0

Coyote Canada Goose 4 2 - 9 6

Coyote Ring-billed Gull 0.8 0.6 - 0 0

Coyote Wild Turkey 0 0 - 1 1

Coyote TOTAL 6 3 - 10 7

Crow American Crow 19 8 800 0 0

Crow Common Raven 8 5 - 0 0

Crow Ring-billed Gull 0.6 0.4 - 0 0

Crow Black-billed Magpie 0.2 0.2 - 0 0

Crow Rock Pigeon* 0.6 0.2 - 0 0

Crow TOTAL 28 14 800 0 0

Eagle Canada Goose 4 4 - 43 42

Eagle Rock Pigeon* 2 4 - 0.1 0.2

Eagle Double-crested Cormorant 6 3 - 0 0
2

Effigy 

Type

Species Number 

Used

Number 

Work 

Tasks

Number 

Dispersed

Number 

Loaned

Number 

Work 

Tasks

Eagle Other Bird (6 sp.)

1 4 7 - 0.8 1

Eagle TOTAL 16 18 - 44 43

Gull Glaucous-winged Gull 168 43 1,074 0 0

Gull Herring Gull 8 5 153 0 0

Gull Ring-billed Gull 8 5 271 0 0

Gull Laughing Gull 4 3 60 0 0

Gull Other Bird (8 sp.)

1 13 5 8 0 0

Gull TOTAL 201 61 1,566 0 0

Human Coyote 7 7 - 0 0

Human Other Mammal (3 sp.)

2 2 3 - 0.2 0.2

Human Herring Gull 7 12 1 0.1 0.2

Human Ring-billed Gull 6 12 - 0.1 0.2

Human Double-crested Cormorant 10 5 - 0 0

Human Other Bird (11 sp.)

1 12 14 12 0.4 0.2

Human TOTAL 44 53 13 0.8 0.8

Vulture Black Vulture 600 381 2,176 17 13

Vulture Turkey Vulture 215 194 867 6 6

Vulture Other Bird (4 sp.) 1 5 3 - 0.5 0.4

Vulture TOTAL 820 578 3,043 24 19 1,2Other species are listed in Appendix 1.

Different types of lights, including floodlights, strobe lights, or revolving lighting units, were used 

by WS to reduce conflicts with coyotes, wolves, and flocking bird species (e.g., European starlings 

and American crows) (Table 4). A small number of work tasks (38.6 annual average) involved 

using mylar or non-mylar flags, mylar tape, and balloons (Tables A1-A4 in Appendix 1). 

Table 4. The annual average number of target mammals and birds hazed with lights by WS in 

Wildlife Damage Management activities from FY16-20 throughout the United States. 

Species Number 

used

Number Work 

Tasks

Number 

Dispersed

Gray Wolf 128 22 0

Coyote 54 22 0

Feral/Free-roaming Dog 5 4 0

Red Fox 5 4 0.2

Mexican Gray Wolf 4 0.6 0

Black-tailed Jackrabbit 3 3 11

Other Mammals (9 sp.)1 10 8 8

TOTAL Mammals 209 64 19

European Starling 82 86 24,101

Mourning Dove 93 107 3,721

American Crow 24 38 4,825

Common Raven 5 4 0

Barn Swallow 11 20 218

Cliff Swallow 6 10 150

Scissor-tailed Flycatcher 13 26 70

Savannah Sparrow 10 15 176
3

Species Number 

used

Number Work 

Tasks

Number 

Dispersed

Northern Cardinal 4 6 9

Northern Mockingbird 1 3 10

Other Passerine (10 sp.) 2 11 14 184

Cooper's Hawk 4 7 6

Crested Caracara 2 4 6

Red-tailed Hawk 3 4 7

Other Raptor (10 sp.) 2 7 12 16

Black-bellied Whistling Duck 4 7 28

Canada Goose 3 3 32

Other Waterbird (3 sp.) 2 2 2 10

Great Egret 5 9 12

Snowy Egret 2 4 5

Cattle Egret 3 4 148

Yellow-crowned Night Heron 2 3 5

Killdeer 14 18 215

White Ibis 2 3 34

Herring Gull 2 2 27

Other Bird (12 sp.) 2 4 8 31

TOTAL Birds 319 418 34,046 1,2Other species are listed in Appendix 1.

1.2.1 Auditory

WS used auditory deterrents, including propane cannons and electronic harassment devices, to 

disperse an annual average of 1,286,180 target birds and 43 target mammals (Tables 5a,b-6a,b). 

WS used propane cannons to protect human health and safety (e.g., airports), aquaculture, and 

agriculture (e.g., sunflower, corn). The main species dispersed with propane cannons were 

European starlings and blackbird species (e.g., red-winged blackbirds and brown-headed 

cowbirds). WS used electronic harassment devices for the protection of human health and safety 

(e.g., airports, disease risk (crow roosts)), and agriculture. Electronic harassment devices for birds 

included programmable speakers that play distress calls or predator calls. Electronic harassment 

devices for mammals included programmable devices that emit startling high-pitched sounds in 

combination with a flashing light.

In some cases, WS may provide supplies or materials of limited availability for use by private 

entities. Propane cannons were loaned to cooperators to disperse bird and mammal species 

(Tables 5a,b). An annual average of 70.4 electronic harassment devices were loaned to disperse 

black bears in 62.8 work tasks. In addition, an annual average of 2.8 electronic harassment 

devices were loaned to disperse white-tailed deer and bird species, such as wild turkeys and 

woodpecker species, in 3.4 work tasks.

Table 5a. The annual average number of propane cannons used to haze target bird species or 

distributed/loaned to cooperators by WS in Wildlife Damage Management activities from FY16-

20 throughout the United States.

Species Number 

used

Number 

Work 

Tasks

Number 

Dispersed

Number 

Loaned

Number 

Work 

Tasks

European Starling 469 272 758,139 3 1
4

Species Number 

used

Number 

Work 

Tasks

Number 

Dispersed

Number 

Loaned

Number 

Work 

Tasks

American Crow 199 167 1,855 1 1

Great-tailed Grackle 54 52 1,527 0 0

Common Grackle 24 23 2,141 390 64

Blackbirds (Mixed Species) 19 18 10,827 1 0.8

Brown-headed Cowbird 33 12 8,779 4 8

Red-winged Blackbirds 20 10 15,849 341 205

Eastern Meadowlark 224 124 5,932 0 0

Mourning Dove 161 120 3,687 0 0

Rock Pigeon* 107 86 3,105 1 0.6

Barn Swallow 85 69 9,314 0 0

Other Passerine (19 sp.)

1 53 34 1,302 97 92

Western Kingbird 28 27 238 0 0

Horned Lark 28 26 299 0 0

Island Collared Dove 15 23 - 0 0

Scissor-tailed Flycatcher 26 21 140 0 0

Eurasian Tree Sparrow 13 20 - 0 0

Cliff Swallow 23 20 9,872 0 0

House Sparrow 11 11 288 0.6 0.6

Eurasian Collared Dove* 8 15 35 0 0

Turkey Vulture 554 555 5,245 0.5 1

Red-tailed Hawk 362 274 426 0 0

Bald Eagle 173 149 155 0.2 0.2

American Kestrel 150 75 152 0 0

Northern Harrier 116 65 96 0 0

Osprey 46 46 64 0 0

Mississippi Kite 32 34 109 0 0

Red-shouldered Hawk 35 32 40 0 0

Cooper's Hawk 18 18 20 0 0

Swainson's Hawk 15 15 78 0 0

Black Vulture 29 15 310 1 1

Other Raptor (8 sp.)

1 8 8 12 0 0

Ring-billed gull 127 97 116,552 0 0

Red-legged Kittiwake 109 26 - 0 0

Herring Gull 45 24 598 0 0

Franklin's Gull 11 11 2,519 0 0

Great Blue Heron 213 175 609 0.1 0.4

Mallard 151 137 2,574 1 0.4

Canada Goose 119 108 5,255 109 67

Other Waterbird (53 sp.)

1 116 96 8,307 16 18

Double-crested Cormorant 61 61 3,090 0.4 0.4

American Coot 61 60 17,347 0 0

Ruddy Duck 54 55 23,564 0 0

Ring-necked Duck 48 48 2,361 0 0

Northern Shoveler 41 41 3,585 0 0

Bufflehead 40 40 746 0 0

Wood Duck 18 18 151 0 0
5

Species Number 

used

Number 

Work 

Tasks

Number 

Dispersed

Number 

Loaned

Number 

Work 

Tasks

Hooded Merganser 13 13 167 0 0

Redhead 11 11 143 0 0

Blue-winged Teal 11 10 204 0.8 1

Great Egret 118 77 726 3 7

Cattle Egret 82 31 2,119 0 0

Killdeer 101 65 574 0 0

Yellow Bittern 13 21 2 0 0

Golden Pacific Plover 12 17 21 0 0

Upland Sandpiper 19 14 651 0 0

Black Francolin 8 14 - 0 0

Other terrestrial nonpasserine (6 sp.)

1

11 10 26 2 3

Unidentifiable bird spp.1 15 15 2,003 0 0

TOTAL 4,766 3,731 1,033,930 973 472

1

Other species are listed in Appendix 1.

Table 5b. The annual average number of propane cannons used to haze target mammal species 

or distributed/loaned to cooperators by WS in Wildlife Damage Management activities from FY16-

20 throughout the United States. 

Species Number 

used

Number 

Work Tasks

Number 

Dispersed

Number 

Loaned

Number 

Work 

Tasks

Northern Raccoon 2 9 - 0 0

Feral Swine 11 7 - 1 0.6

Coyote 17 6 5 0.2 0.2

White-tailed deer 6 3 11 5 3

Eastern Gray Squirrel 0.7 3 0.4 0 0

Woodchuck 1 2 - 0 0

Feral/Free-roaming Dog 1 1 1 0 0

Red fox 2 1 0.8 0 0

Other Mammal (12 sp.)

1 12 4 0.8 4 4

TOTAL 53 36 19 10 8

1

Other species are listed in Appendix 1.

Table 6a. The annual average number of electronic harassment devices used to haze target bird 

species or by WS in Wildlife Damage Management activities from FY16-20 throughout the United 

States. 

Species Number 

used

Number 

Work Tasks

Number 

Dispersed

European Starling 227 227 192,926

Great-tailed Grackle 4 4 584

Brown-headed Cowbird 4 4 1,045

Blackbirds (Mixed Species) 3 3 42,290

Eastern Meadowlark 9 5 169

American Crow 12 12 429

Mourning Dove 14 14 604
6

Rock Pigeon 10 10 340

Other Passerine sp.1 10 10 586

Canada Goose 24 22 672

Ring-billed Gull 27 27 3,967

Laughing Gull 15 15 4,516

Killdeer 15 14 142

Herring Gull 9 9 1,709

Great Blue Heron 9 9 32

Other Waterbird sp.1 26 25 1,973

Wild Turkey 2 2 7

Bald Eagle 19 18 28

Red-tailed Hawk 12 7 11

Turkey Vulture 11 11 105

American Kestrel 11 6 25

Northern Harrier 7 2 3

Osprey 6 6 14

Black Vulture 3 3 61

Other Raptor sp.1 5 5 12

Unidentified Mixed Mammal and Bird sp. 9 9 -

TOTAL 503 479 252,250

1

Other species are listed in Appendix 1.

Table 6b. The annual average number of electronic harassment devices used to haze target 

mammal species or by WS in Wildlife Damage Management activities from FY16-20 throughout 

the United States. 

Species Number used Number Work 

Tasks

Number Dispersed

Gray Wolf 30 22 -

White-tailed Deer 4 4 22

Louisiana Black Bear T&E1 3 3 0.2

Coyote 2 2 0.6

Other Mammal sp.2 2 2 0.8

Black Bear 0.4 0.4 0.8

Coyote and Wolf 0.4 0.2 -

Red Fox 0.4 0.4 -

Feral/Free-ranging Cat 0.2 0.4 -

Striped Skunk 0.2 0.4 -

Steller Sea Lion 0.4 0.4 -

TOTAL 43 33 24 1T&E = Federally listed threatened and endangered species – the Louisiana black bear is no longer federally listed but 

included.

2

Other species are listed in Appendix 1.

2 HAZARDS

2.1 Human Health and Safety Hazards

The use of nonchemical deterrents may affect human health and safety due to auditory 

disturbances related to the various deterrent devices or their installation in targeted damage

areas. However, WS personnel are trained or instructed to use nonchemical deterrents in WDM 

so that human health and safety are prioritized. For example, training and instruction on installing 
7

nonchemical deterrents and proper use of appropriate personal protective equipment (PPE) are 

provided. Appropriate PPE includes hearing protection and eye protection as appropriate, which 

decrease the risks associated with the use of nonchemical deterrents.

2.1.1 Visual

Visual deterrents have little potential to affect human health and safety. Visual deterrents include 

passive harassment methods like flags, effigies, inflatable deterrents, and lights. Preparing 

effigies from bird carcasses poses a safety risk to the person conducting the action. In addition to 

the use of sharps for preparation of the effigy, there is a potential for exposure to infectious 

diseases. WS personnel may get injuries from using sharps during effigy preparation, including 

cuts, abrasions, or punctures. It is possible for an employee to accidentally poke or cut 

themselves, which could expose them to an infectious zoonotic disease, similar to risks faced by

health care professionals. All WS personnel that use sharps, in collaboration with the APHIS 

Biosafety Officer, are required to watch the “Safe Handling and Disposal of Sharps Training 

Video” and adhere to Standard Operating Procedure HS/WS 001.00 “Safe Handling and Disposal 

of Sharps in Laboratory and Field Settings within Wildlife Services.”

WS personnel should carry a medical alert card so medical personnel know that diseases from

animal exposure are a potential source of sickness. Animal bites and scratches must be reported

(federal forms CA-1 or -2 and the APHIS Online First Report). Personnel who handle or are

exposed to diseased wildlife are trained using disease-specific training manuals. Training

manuals include instructions for collecting samples specific to that disease, sample storage, and

sample shipping for testing. There are also in-person training courses, including Necropsy Lab

and Wildlife Disease Preparedness Training, available for all WS employees through the WS

National Training Academy.

Other potential hazards include cuts or abrasions from loose wires, snags, or sharp edges on the 

equipment and possible strain from labor and maneuvering of materials. Most injuries occur while 

setting or maintaining fencing for flagging or installing lights or effigies due to the installation of tposts or other structural supports. Remote-controlled vehicles are triggered by attending 

personnel at a distance from the dispersed wildlife, reducing any hazard from the action to 

personnel or the public.

Driving vehicles for surveys and transportation among field sites carries the typical hazards that 

any driver of a vehicle may be subject to. The APHIS Job Hazard Analysis identifies “physical 

trauma from various impacts” as a potential hazard for driving automobiles/box trucks in urban, 

suburban, and rural areas. However, when using vehicles for wildlife patrols and runway sweeps 

at airports, drivers must maintain awareness of aircraft movements and other airport vehicles in 

addition to monitoring for wildlife and attempting vehicle harassment. Vehicles used to survey 

wildlife in agricultural fields and off paved roads add additional hazards.

2.1.2 Auditory

The use of auditory deterrents has some potential to affect human health and safety due to the 

potential for repeated exposure to decibels higher than the Occupational Safety and Health 

Administration (OSHA) recommends. OSHA regards noise levels over 85 decibels (dB) averaged 

over 8 hours, or an 8-hour time-weighted average, as potentially damaging. Propane cannons

produce 120-dB intermittent sounds (measured within 1 m of the deterrent). A recent study 

measured the sound attenuation of propane cannons and found that at 340 m (1,115 ft) the sound 

intensity of the propane cannon no longer exceeded ambient noise (Duttenhefner and Klug 2024). 
8

Electronic distress signals and other electronic high-pitched sounds may also present a hazard 

to personnel or the public. Sound source noise emission levels for nonchemical deterrents range 

from 45-140 dBA (Table 7). Adverse effects of noise can include hearing loss, communication 

interference, sleep interference, physiologic responses, and annoyance (USEPA 1974).

Table 7. Sound source noise emission levels for nonchemical deterrents and other reference 

sources.

Equipment Maximum Sound Level 

(dBA1 Lmax) – 50 feet 

from Source

Reference

All-Terrain Vehicle (ATV) 75 (Berger et al. 2015)

Air Horn / Deterrent Device 83 (FHWA 2006;2008)

Birds – Crows 45 (Berger et al. 2015)

Birds – Woodpeckers 50 (Berger et al. 2015)

Dog Barking 60 (Berger et al. 2015)

Pick-up Truck 55 (FHWA 2006;2008)

Propane Cannon 120 (Silva et al. 2021)

12 Gauge Shotgun 140 (Berger et al. 2015) 1dBA – A-weighted decibel

2.2 Environmental Hazards

The primary environmental hazard that may result from nonchemical deterrents is a disturbance 

to nontarget animals due to nonchemical deterrent use. There is also a fire risk from propane 

cannons, particularly in grassy areas during dry periods. The area around propane cannons 

should be kept clear of fire hazards such as tall grass or shrubs, and the barrel should not be 

aimed at the fuel tank or in the direction of users (Greer and O'Connor 1994). Using elevated 

platforms in grassy areas can reduce the chance of fire. The use of vehicles may lead to erosion 

problems or injuries to nontarget animals, and improper or inappropriate use of any of the 

harassment techniques may result in disturbances to nesting animals. Nontarget animals may be 

affected by loss or inaccessibility to food sources or other habitat components. No component of 

nonchemical deterrents would contaminate water or result in the bioaccumulation of chemicals or 

other hazardous materials.

3 RISKS

3.1 Human Health and Safety Risks

Nonchemical methods available to alleviate or prevent damage associated with birds, mammals, 

and reptiles pose minimal risks to human safety. Although some safety risks would likely occur,

those risks would be minimal when methods are used appropriately and in consideration of human 

safety.

WS employees are well-trained in safely and properly using nonchemical deterrents, including 

vehicles. Activities are generally conducted in areas with minimal human activity (e.g., in areas 

closed to the public), substantially limiting risks to the public. Short-term human disturbance may 

result from using auditory nonchemical deterrents. Visual deterrents have negligible human health 

or safety risk.

During FY16-FY20, WS employees had an annual average of 0.6 injuries directly related to 

nonchemical deterrent deployment. Two employees injured digits (scalpel slip, barbed wire fence 
9

puncture), and one employee injured an eye while repairing a propane cannon. Other injuries,

such as slips and falls, strains, and sprains, may occur while performing dispersal activities or 

deploying nonchemical deterrents but are not particular to any nonchemical deterrent activity.

These injuries are discussed in the “Introduction to Risk Assessments for Methods Used in WDM” 

(USDA Wildlife Services 2017).

During FY16-FY20, WS employees had an annual average of 11 vehicle incidents that occurred 

on airports, or other facilities or on farmland. No personnel injuries occurred during any incidents.

Examples of incidents include sliding off narrow or muddy roads or hitting unseen objects (e.g., 

gates, fence posts, tree stumps) in tall grass or berms.

3.1.1 Visual

The use of motorized vehicles for wildlife harassment is the primary risk to human health and 

safety. WS employees may not be driving on paved roads, or roads at all. Risks may include 

potential rollovers, fires, and crashes. However, incidents that occurred during FY16-20 were 

minor and resulted in no injuries to WS employees or the public.

Many visual nonchemical methods are passive devices or only activated when triggered by 

attending personnel (e.g., lights, effigies, flags, fladry). Potential injury may occur when installing 

fencing for flags or fladry, or when preparing effigies. Risks to human health and safety have been 

minimized for WS employees who are well-trained to use sharps in preparation of effigies

properly. As required by WS Directive 2.635, "Zoonotic Diseases and Personal Protective 

Equipment," all WS personnel who handle or are exposed to wildlife will be provided with 

biological sampling, disease exposure safety training, and PPE training. Use of PPE such as 

examination gloves, cut-resistant gloves, splash-proof aprons, protective eyewear, face masks, 

and Tyvek® coveralls and shoe covers while handling wildlife can significantly minimize exposure 

to zoonotic diseases. Injuries to WS personnel from tools used to prepare effigies are anticipated 

to be minimal during any given year.

Overall, risks to workers are low based on WS personnel being trained in the proper use of 

vehicles and the use and set up of nonchemical deterrents in accordance with WS Directive 2.635. 

Risks to the general population are negligible because site selection and activity timing minimize 

public exposure.

3.1.2 Auditory

Some risk of fire, bodily harm, hearing loss, and other noise related effects exist from using 

propane cannons. WS proper use and application of these devices and attention to the potential 

risks of these methods can help prevent risk. In addition, noise levels over 70 dB may be 

controlled by local regulations. For example, Hawaii requires a permit to allow activities that may 

exceed maximum permissible levels and durations (Silva et al. 2021).

Propane cannons are generally inappropriate for urban/suburban areas due to the repeated loud 

noises, which many people would consider a serious and unacceptable nuisance and potential 

health threat (e.g., hearing damage). In addition, propane cannons are more effective for 

migratory and hunted species that associate danger with loud noises, and less effective for 

resident species that are well established in an area (e.g., resident geese in urban/suburban 

areas) (Marsh et al. 1991).

3.2 Environmental Risks
10

Like the use of visual and physical dispersal methods, the intent with the use of auditory dispersal 

methods, such as electronic hazing devices and propane cannons, is to elicit a flight response in 

target bird and mammal species by mimicking distress calls or producing a novel or adverse 

noise. Of concern are the possible negative physiological and/or behavioral effects that negative 

stimuli of any dispersal method could cause, which could reduce the fitness of nontarget animals 

or the ability of nontarget animals to survive, especially if the exposure to the stressor was chronic. 

The stress from dispersal methods could negatively affect an animal's health, interfere with the 

raising of young, and/or increase energy needs. However, for effects to occur, nontarget animals 

would have to be within hearing distance when WS personnel used an auditory method, and the 

resulting noise stimuli would have to elicit a negative response. Like other non-lethal methods, 

WS personnel would not use those methods over large geographical areas or at such an intensity 

level that essential resources (e.g., food sources, habitat) would be unavailable for extended 

durations or over such a wide geographical scope that long-term adverse effects would occur to 

a species' population. Target animals are also susceptible to the negative physiological and/or 

behavioral effects of dispersal techniques. In some cases, the target birds are being dispersed 

from hazardous areas, which could also have a negative impact, for example, oil spills or airports. 

Environmental risks are limited to unintentional disturbances of nontarget animals that may be in 

the area of a targeted animal. However, the risks are at a minimum because the deterrents are 

nonchemical. WS understands the disturbances that may result from these deterrents and 

considers them when targeting animals such as nesting animals that are sensitive to such 

disturbances. APHIS does not recommend practices or conduct activities that adversely affect 

federally threatened or endangered species.

There is a small chance of fire due to propane cannon use. Only one incident of fire associated 

with a propane cannon was reported between 2015 and 2022 (the period for which injury and 

accident data were available). A small grass fire (1-1.5 acres) occurred, likely due to a propane 

cannon during dispersal activities. The fire was put out without further damage or injury to 

personnel or wildlife.

4 UNCERTAINTIES AND CUMULATIVE EFFECTS

Uncertainty in this risk assessment is minimal because WS has several decades of experience 

using the selected methods as nonchemical deterrents. The knowledge gained from this 

experience has helped reduce risks associated with nonchemical deterrents, especially regarding

human health and safety risks due to auditory deterrents that may create disturbances, such as 

propane cannons.

Cumulative impacts could potentially occur to target and nontarget animals. However, cumulative 

impacts are addressed in National Environmental Policy Act documents and to date have been 

found not to be significant to any native population. Additionally, the "Introduction to WS Methods 

Risk Assessments” (USDA Wildlife Services 2017) assesses all species taken by WS from FY11 

to FY15 and shows no significant impacts from a population standpoint. From a human health 

perspective, using nonchemical deterrents in WDM will not have any known cumulative impacts.

5 SUMMARY

Nonchemical deterrents are used in integrated WDM to reduce the impacts of damage caused by 

wildlife, such as deer and avian species, but the effectiveness of deterrents varies. An animal's 

visual and auditory senses affect how it will respond to any given stimulus, and habituation to the 

stimulus is common in the long-term. Nonchemical deterrents include vehicles, propane cannons, 
11

distress recordings/signals, fladry, mylar/reflective tape, balloons, and flashing lights. These 

deterrents all aid in reducing a target animal's impact on human and natural resources by utilizing 

the animals' physical, auditory, or visual cues to deter them from the area of damage or threat. 

Because these types of deterrents are nonchemical, the hazards and risks associated with their 

use are relatively low. Disturbances from auditory deterrents, such as propane cannons, and 

visual deterrents, such as vehicles, are the main risks regarding human health, safety, and the 

environment. The noise from propane cannons can cause disturbance to humans and nontarget 

animals depending on their proximity to the device. WS personnel are trained to avoid nontarget 

species and human activity when using nonchemical deterrents, which decreases any potential

hazards and risks. Operation of vehicles carries risk but use as a visual deterrent can add to this 

risk due to the situations vehicles are driven (e.g., airports, agricultural fields). 

6 LITERATURE CITED

Avery, M.L., J.S. Humphrey, E.A. Tillman, K.O. Phares, and J.E. Hatcher. 2002. Dispersing 

vulture roosts on communication towers. Journal of Raptor Research 36:45-50.

Avery, M.L., E.A. Tillman, and J.S. Humphrey. 2008. Effigies for Dispersing Urban Crow Roosts. 

Proceedings of the Vertebrate Pest Conference 23.

Avery, M.L., and S.J. Werner. 2017. Frightening devices. Pages 159-174 in G. M. Linz, andM. L. 

Avery, eds. Ecology and Management of Blackbirds (Icteridae) in North America. CRC 

Press, Boca Raton, FL.

Berger, E.H., R. Neitzel, and C.A. Kladden. 2015. Noise NavigatorTM Sound Level Database with 

Over 1700 Measurement Values (Version 1.8). 

https://multimedia.3m.com/mws/media/888553O/noise-navigator-sound-level-hearingprotection-database.pdf accessed January 11, 2024.

Breck, S.W., J.T. Schultz, D. Prause, C. Krebs, A.J. Giordano, and B. Boots. 2023. Integrating 

robotics into wildlife conservation: testing improvements to predator deterrents through 

movement. PeerJ 11:e15491.

Bruggers, R.L., J.E. Brooks, R.A. Dolbeer, P.P. Woronecki, R.K. Pandit, T. Tarimo, A.-

I.C.R.P.o.E. Ornithology, and M. Hoque. 1986. Responses of pest birds to reflecting tape 

in agriculture. Wildlife Society Bulletin 14:161-170.

Cleary, E., and R. Dolbeer. 2005. Wildlife hazard management at airports: A manual for airport 

personnel.

Cummings, J.L., C.E. Knittle, and J.L. Guarino. 1986. Evaluating a pop-up scarecrow coupled 

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14
15

7 PREPARERS

7.1 APHIS WS Methods Risk Assessment Committee

Writers for "Use of Nonchemical Deterrents in Wildlife Damage Management Risk Assessment":

Primary Writer: Shelagh DeLiberto 

Position: USDA-APHIS-Wildlife Services (WS), Operational Support Staff, Environmental 

Coordinator, Fort Collins, CO

Education: BA Biology and Environmental Science – Ithaca College; MS Wildlife Biology –

Colorado State University 

Experience: Twenty years of service in APHIS conducting wildlife research. Two years of 

experience preparing categorical exclusions and environmental analyses in compliance 

with the National Environmental Policy Act.

Writer/Editor: Thomas C. Hall

Position: USDA-APHIS-WS, Operational Support Staff, Staff Wildlife Biologist, Fort Collins, CO

Education: BS Biology (Natural History) and BA. Psychology – Fort Lewis College; MS Wildlife 

Ecology – Oklahoma State University

Experience: Special expertise in wildlife biology, identification, ecology, and damage 

management. Thirty-two years of service in APHIS Wildlife Services including operations 

and research in CO for research and OR, GU, CA, OK, and NV for operations conducting 

a wide variety of programs including bird damage research and management, livestock 

protection (predators and birds), invasive species management, wildlife hazard 

management at airports, property and natural resource protection including waterfowl, 

brown tree snake, feral swine, rodent, and beaver damage management. Expert in 

preparing environmental documents for WS programs to comply with the National 

Environmental Policy Act and the Endangered Species Act. For quick-kill traps specifically, 

used all types of quick-kill traps in WDM and supervised employees that used them in their 

duties. 

Editors/Contributors for "The Use of Nonchemical Deterrents in Wildlife Damage Management 

Risk Assessment":

Editor: Todd Felix

Position: Wildlife Biologist (Environmental Coordinator)

Education: B.S., M.S., Biology

Experience: 24 years as a Wildlife Biologist for APHIS Wildlife Services.

Data Contributor: Joey Millison

Position: USDA-APHIS-WS Information and Technology (IT), Junior Applications Developer

Education: Information and Technology coursework from various sources

Experience: Eleven years of experience in APHIS, WS Management Information System (MIS.) 

Group. Retrieves WS field data from the MIS for writers, reviewers, and editors.

Editor: Chris Croson

Position: USDA-APHIS-WS, Operational Support Staff, Staff Wildlife Biologist, Mooresville, NC

Education: BS Wildlife Biology, Virginia Tech; Masters of Strategic Studies, U.S. Army War 

College

Experience: Twenty-three years of service in APHIS Wildlife Services, including operations and 

operational support. Supervised WDM operations in PA and WV for a variety of operations, 
16

including rabies management, livestock protection, wildlife hazard management at airports, 

deer damage management, and several other urban WDM programs. Special expertise in 

preparing environmental documents for WS programs to comply with the NEPA and 

Endangered Species Act.

7.2 Internal Reviewers

USDA APHIS Wildlife Services

Reviewer: David Allaben 

Position: State Director

Education: BS in Wildlife and Fisheries Management and Natural Resources

Experience: 28-years wildlife damage management with APHIS Wildlife Services-SC, VA, NH, 

VT. Expertise in agricultural crop damage, aviation safety, urban wildlife conflicts and natural 

resource protection. 

Reviewer: Scott Beckerman

Position: USDA APHIS Wildlife Services, State Director/ Supervisory Wildlife Biologist, 

Springfield, IL

Education: BS and MS in Fisheries and Wildlife Management, University of Missouri-Columbia

Experience: Expertise in wildlife damage management and wildlife biology. Thirty one years of 

service in APHIS Wildlife Services operational programs in MO, IA, WI, CA, and IL. 

Experience in mitigating conflicts caused by a wide variety of wild animals including, 

ungulates, migratory birds/waterfowl, predators, rodents, and invasive species including feral 

swine.

Reviewer: Matt Cleland

Position: USDA APHIS Wildlife Services, State Director/ Supervisory Wildlife Biologist, Port 

Allen, LA

Education: BS in Wildlife Management, Washington State University

Experience: Expertise in wildlife damage management and wildlife biology. Twenty-four years 

of service in APHIS Wildlife Services operational programs in WA, CA, TN, KY and 

LA. Experience in mitigating conflicts caused by a wide variety of wild animals including 

ungulates, migratory birds/waterfowl, predators, rodents, reptiles and invasive species 

including feral swine and nutria.

Reviewer: Aaron Guikema

Position: USDA APHIS WS, State Director, Pittstown, NJ

Education: B.S. in Fisheries and Wildlife Management, Lake Superior State University

Experience: Twenty-three year of wildlife damage management with APHIS Wildlife Services.

Reviewer: Nokota Harpster

Position: USDA-APHIS-WS Staff Wildlife Biologist for Pennsylvania WS

Education: Bachelor of Science-Wildlife Conservation from Juniata College.

Experience: 8 years working for WS.

Reviewer: Daniel Hirchert

Position: USDA-APHIS-WS, State Director, Sun Prairie, WI

Education: BS in Field Biology, University of Wisconsin
17

Experience: Twenty-eight years of service in wildlife damage management with APHIS Wildlife 

Services and Wisconsin Department of Natural Resources. Expertise in agricultural crop 

damage, aviation safety, urban wildlife conflicts and natural resource protection. 

Reviewer: Page Klug 

Position: USDA-APHIS-WS-NWRC, Supervisory Research Wildlife Biologist, Fargo, ND

Education: PhD Biology – Kansas State University; MS Biology – University of Nebraska at 

Omaha; BS Environmental Science and Policy – Drake University

Experience: Expertise in wildlife biology and wildlife damage management research. Tenure of 

eight years as North Dakota Field Station leader for USDA-APHIS-WS-NWRC focusing on 

bird damage to agriculture, including the use of frightening devices, wildlife repellents, and 

evading strategies. Experience in wildlife damage management includes invasive and native 

birds (e.g., blackbirds, starlings, and parakeets) and invasive reptiles (e.g., brown treesnakes 

and tegus). Optimization of methods takes into account avian biology at multiple biological 

levels and incorporates the influence of landscape ecology at various scales.

Reviewer: Dustin Ranglack

Position: USDA-APHIS-WS-NWRC, Supervisory Research Wildlife Biologist, Millville, UT

Education: PhD Ecology – Utah State University; BS Wildlife Science – Utah State University

Experience: Expertise in wildlife biology and wildlife damage management research. Tenure of 

1.5 years as Utah Field Station leader and Predator Project leader for USDA-APHIS-WSNWRC focusing on predator damage to livestock, including the use of frightening devices, 

wildlife repellents, and non-lethal strategies. Spent 6.5 years teaching wildlife management, 

including wildlife damage management, at the University of Nebraska – Kearney. Experience 

in wildlife damage management includes mammalian predators (coyotes, wolves, mountain 

lions, bears) and ungulates (elk, deer, bison, pronghorn). Wildlife damage research focuses 

on evaluating the efficacy of both non-lethal and lethal techniques to reduce human-predator 

conflict. 

Reviewer: Jeff Rumbaugh

Position: USDA-APHIS-Wildlife Services, Staff Wildlife Biologist, Moseley, VA

Education: BS in Wildlife and Fisheries Resources, West Virginia University

Experience: Twenty-six years of service with WS in the SC and VA programs; expertise with a 

wide variety of damage management techniques for many species of migratory birds and 

mammals.
18

APPENDIX 1. "Other Species" Included in Tables 

Table 1

Other dove = common ground-dove, zenaida dove

Other larid = pomarine jaeger, parasitic jaeger, long-tailed jaeger, black-legged kittiwake, blackheaded gull, Heermann’s gull, Iceland gull, glaucous gull, white tern, least tern, gull-billed tern, 

black tern, common tern, arctic tern, royal tern, black skimmer,

Other waterfowl = Ross’s goose, feral domestic graylag goose*, trumpeter swan, mottled duck, 

spectacled eiderT&E, king eider, common eider, harlequin duck, surf scoter, white-winged 

scoter, black scoter, long-tailed duck, red-breasted merganser

Other corvid = Canada jay, Steller’s jay, blue jay, California scrub-jay, Woodhouse’s scrub-jay, 

yellow-billed magpie

Other raptor = swallow-tailed kite, golden eagle, sharp-shinned hawk, American goshawk, 

common black hawk, Harris’s hawk, broad-winged hawk, Hawaiian hawkT&E, eastern screechowl, great horned owl, snowy owl, northern hawk owl, northern pygmy-owl, burrowing owl, 

barred owl, great gray owl, boreal owl, merlin, gyrfalcon, prairie falcon

Other waterbird = pied-billed grebe, horned grebe, red-necked grebe, eared grebe, western 

grebe, red-throated loon, Pacific loon, common loon, black-footed albatross, fork-tailed stormpetrel, wedge-tailed shearwater, Newell’s shearwaterT&E, great frigatebird, brown booby, 

anhinga, pelagic cormorant 

Other wading bird = common gallinule, whooping craneT&E, wood storkT&E, American bittern, least 

bittern, tricolored heron, reddish egret, green heron, yellow-crowned night-heron, roseate 

spoonbill

Other shorebird = American oystercatcher, black oystercatcher, Wilson’s plover, mountain plover, 

bristle-thighed curlew, Hudsonian godwit, marbled godwit, black turnstone, red knotT&E, sharptailed sandpiper, stilt sandpiper, rock sandpiper, white-rumped sandpiper, buff-breasted 

sandpiper, pectoral sandpiper, short-billed dowitcher, American woodcock, spotted 

sandpiper, solitary sandpiper, wandering tattler, Wilson’s phalarope, red-necked phalarope

Other gallinaceous birds = northern bobwhite, Gambel’s quail, ruffed grouse, spruce grouse, 

willow ptarmigan, rock ptarmigan, gray partridge, Indian peafowl

Other aerialists = lesser nighthawk, common nighthawk, white-throated swift, chimney swift, 

violet-green swallow, northern rough-winged swallow

Other non-passerine birds = smooth-billed ani, greater roadrunner, belted kingfisher, Lewis’s 

woodpecker, red-headed woodpecker, pileated woodpecker, budgerigar, monk parakeet 

Other grassland passerines = gray kingbird, black phoebe, eastern phoebe, Say’s phoebe, 

Loggerhead shrike, northern shrike, grasshopper sparrow, chipping sparrow, American tree 

sparrow, vesper sparrow, Lincoln’s sparrow, dicksissel, bobolink

Other forest passerine = black-capped chickadee, cedar waxwing, red-breasted nuthatch, gray 

catbird, brown thrasher, western bluebird, Townsend’s solitaire, Swainson’s thrush, hermit 

thrush, varied thrush, common redpoll, white-winged crossbill, lesser goldfinch, yellow 

warbler, yellow-rumped warbler, Townsend’s warbler, Wilson’s warbler, western tanager, 

indigo bunting

Invasive Passerines = red-whiskered bulbul, warbling white-eye

Other predator = Arctic fox, badger, bobcat, brown bear (grizzly), feral/free-roaming dog, gray fox, 

lynx, mink, northern raccoon, northern sea otter, gray wolf, river otter, short-tailed weasel, 

small Indian mongoose, striped skunk, swift fox, Virginia opossum

Other rabbit/rodent = American beaver, Belding’s ground squirrel, common muskrat, eastern fox 

squirrel, eastern gray squirrel, feral domestic European rabbit, North American porcupine, 
19

nutria, red squirrel, Richardson’s ground squirrel, snowshoe hare, swamp rabbit, white-tailed 

antelope squirrel, white-tailed jackrabbit, woodchuck, yellow-bellied marmot.

Other mammal = caribou, collared peccary, feral swine, free-roaming cattle, free-roaming sheep, 

gemsbok, nine-banded armadillo, pronghorn, unidentified bat (9 sp.)

Other reptile = American alligator, black and white tegu, green iguana, river cooter 

Table 2

Other waterbird = American coot, Double-crested cormorant, bufflehead, redhead, ruddy duck, 

lesser scaup, Northern shoveler, Atlantic brant goose, greater white-fronted goose, ring-billed 

gull, mute swan*

Other passerine bird = rock pigeon*, European starling*

Other raptor = Black vulture, turkey vulture

Other mammal = white-tailed deer, woodchuck

Table 3

Eagle Effigy

Other waterbird = Cackling goose, mallard, ring-billed gull

Other passerine bird = European starling*, house sparrow*

Other terrestrial non-passerine bird = wild turkey

Gull Effigy

Other waterbird = Canada goose, great blue heron, California gull, western gull, great blackbacked gull, 

Other passerine bird = American crow, rock pigeon* European starling*

Human Effigy

Other mammal = Feral/free-ranging dog, red fox, white-tailed deer

Other waterbird = neotropic (olivaceous) cormorant, Canada goose, mallard, cattle egret, 

American white pelican

Other passerine bird = American crow, common raven, European starling*

Other raptor = Bald eagle, black vulture, turkey vulture

Vulture Effigy

Other waterbird = Great blue heron

Other passerine bird = Common raven

Other raptor = Bald eagle, northern crested caracara

Table 4

Other mammal = Eastern cottontail rabbit, raccoon, black bear, fox squirrel, American beaver, 

white-tailed deer, feral swine, Virginia opossum, striped skunk

Other passerine bird = common grackle, great-tailed grackle, red-winged blackbird, white-winged 

dove, rock pigeon*, blue jay, loggerhead shrike, eastern meadowlark, house finch, eastern 

bluebird

Other raptor = Turkey vulture, osprey, American kestrel, broad-winged hawk, northern harrier, 

red-shouldered hawk, Swainson's hawk, black vulture, barn owl, great horned owl

Other waterbird = Double-crested cormorant, mottled duck, American coot, 

Other bird = Great blue heron, little blue heron, white ibis, roseate spoonbill, semipalmated plover, 

upland sandpiper, Forster's tern, laughing gull, ring-billed gull, common nighthawk, belted 

kingfisher, pileated woodpecker
20

Table 5a

Other passerine bird = Common raven, fish crow, black drongo, American robin, Eastern kingbird, 

tree swallow, bank swallow, Northern rough-winged swallow, purple martin, chimney swift, 

house finch, western meadowlark, savannah sparrow, boat-tailed grackle, yellow-headed 

blackbird, Brewer's blackbird, American pipit, Northern mockingbird, black-billed magpie

Other raptor = Sharp-shinned hawk, peregrine falcon, broad-winged hawk, Northern crested 

caracara, merlin, great horned owl, burrowing owl

Other waterbirds = Laughing gull, great black-backed gull, lesser black-backed gull, glaucuswinged gull, Bonaparte's gull, long-tailed jaeger, whiskered tern, common tern, black tern, 

gull-billed tern, Caspian tern, green heron, little blue heron, American bittern, tri-colored heron, 

lesser scaup, gadwall, canvasback, mottled duck, green-winged teal, black-bellied whistling 

duck, cinnamon teal, American wigeon, American black duck, Northern pintail, Fulvous 

whistling duck, feral duck*, anhinga, lesser snow goose, greater white-fronted goose, greater 

snow goose, trumpeter swan, tundra swan, ruddy turnstone, willet, white ibis, glossy ibis, least 

sandpiper, sanderling, whimbrel, dunlin, wood sandpiper, black-bellied plover, greater 

yellowlegs, lesser yellowlegs, semipalmated plover, American avocet, Wilson's snipe, snowy 

egret, black-crowned night heron pied-billed grebe, American white pelican, brown pelican

Other terrestrial non-passerine bird = Common nighthawk, nighthawk spp., wild turkey, sandhill 

crane, Northern flicker, California Quail

Table 5b

Other mammal = Caribou, elk, pronghorn, striped skunk, white-tailed jackrabbit, black-tailed 

jackrabbit, bobcat, feral/free-ranging cat, black bear, gray wolf, arctic fox, gray fox

Table 6a

Other waterbirds = American coot, double-crested cormorant, mallard, ruddy duck, Northern 

shoveler, green-winged teal, American wigeon, Hawaiian goose (T&E), great black-backed 

gull, California gull, Caspian tern, Forster's tern, cattle egret, great egret, snowy egret, longbilled curlew, sanderling, willet, greater yellowlegs, lesser yellowlegs, upland sandpiper

Other passerine birds = red-winged blackbird, boat-tailed grackle, common grackle, western 

meadowlark, Eurasian collared dove*, white-winged dove, scissor-tailed flycatcher, American 

robin, horned lark, barn swallow, cliff swallow, chimney swift

Other raptor = Crested caracara, merlin, peregrine, red-shouldered hawk, sharp-shinned hawk, 

Swainson's hawk, barn owl

Table 6b

Other mammal = Black bear, red fox, feral/free-ranging cat, striped skunk, Steller sea lion

Table A1. The annual average number of flags (mylar or non-mylar) used to haze target bird 

species or distributed to cooperators by WS in WDM activities from FY16-20 throughout the 

United States. 

Species Number 

used

Number 

Work 

Tasks

Number 

Dispersed

Number 

Distributed

Number 

Work 

Tasks

American Crow 1 0.2 - - -

Common Raven 0.2 0.2 - - -
21

Species Number 

used

Number 

Work 

Tasks

Number 

Dispersed

Number 

Distributed

Number 

Work 

Tasks

Sandhill Crane - - - 0.2 0.2

Mallard 0.05 0.2 - - -

Northern Shoveler 0.05 0.2 - - -

Common Merganser - - - 0.2 0.2

Double Crested Cormorant 8 0.6 - - -

Canada Goose 42 9 11 81 16

Cackling Goose 25 0.2 - - -

Lesser Snow Goose 2 0.2 - - -

Greater Snow Goose - - - 1 0.2

Bald Eagle 1 0.2 - - -

Red-tailed Hawk 1 0.4 - 1 1

Red-shouldered Hawk - - - 0.2 0.2

Barred Owl - - - 0.2 0.2

Black Vultures 1 0.2 - - -

Turkey Vultures 1 0.2 - - -

Rock Pigeons* 0.1 0.2 - 0.4 0.2

Northern Mockingbird - - - 0.4 0.2

American Robin - - - 0.4 0.4

European Starling 1 0.2 - 0.9 0.4

Common Grackles - - - 0.2 0.2

House Sparrow* - - - 0.4 0.2

Wild Turkey 0.2 0.2 - 4 0.8

Downy Woodpecker - - - 1 0.8

Hairy Woodpecker - - - 1 1

Pileated Woodpecker - - - 0.4 0.4

Red-headed Woodpecker 0.2 0.2 - 0.2 0.2

Total 84 13 11 93 23

Table A2. The annual average number of rolls of mylar tape used to haze target species or 

distributed to cooperators by WS in WDM activities from FY16-20 throughout the United States.

Species Number 

used

Number 

Work 

Tasks

Number 

Dispersed

Number 

Loaned

Number 

Work

Tasks

American Crow - - - 0.6 0.4

Common Raven - - - 0.4 0.2

Red-winged Blackbird 0.2 0.2 - - -

Blackbirds (Mixed Species) - - - 1 0.6

Common Grackles - - - 0.2 0.2

Mourning Dove 0.02 0.2 - - -

Rock Pigeon 0.02 0.2 - 0.2 0.2

House Sparrow 0.02 0.2 - 0.2 0.2

European Starling 13 2 - 0.4 0.2

Northern Cardinal - - - 0.4 0.4

American Robin - - - 0.6 0.6

Barn Swallow - - - 0.2 0.2
22

Species Number 

used

Number 

Work 

Tasks

Number 

Dispersed

Number 

Loaned

Number 

Work

Tasks

Bald Eagle - - - 0.4 0.2

American Kestrel 0.5 0.4 - - -

Broad-winged Hawk - - - 0.4 0.4

Cooper's Hawk - - - 0.6 0.4

Northern Goshawk - - - 0.2 0.2

Red-shouldered Hawk - - - 0.2 0.2

Red-tailed Hawk 0.2 0.2 - 2.6 2

Osprey - - - 0.8 0.2

Barred Owl - - - 0.4 0.2

Black Vulture 0.2 0.2 - - -

Mallard 0.8 0.2 - 0.2 0.2

Canada Goose 21 8 49 13.2 7

Lesser Snow Goose 0.2 0.2 - 0.4 0.2

Franklin's Gull - - - 0.1 0.2

Glaucous-winged Gull 0.4 0.8 - - -

Ring-billed Gull 0.02 0.2 - 0.1 0.2

Wild Turkey 0.6 0.6 - 5.6 5

Northern Flicker 0.2 0.2 - 0.2 0.2

Downy Woodpecker - - - 3.5 3

Hairy Woodpecker - - - 5.3 2

Pileated Woodpecker - - - 0.6 0.6

Red-bellied Woodpecker - - - 0.6 0.6

Yellow-bellied Sapsucker - - - 0.4 0.4

Total 37 14 49 39 27

Table A3. The annual average number of flags/tape used as fladry to haze target mammal species 

or distributed to cooperators by WS in WDM activities from FY16-20 throughout the United States.

Species Number 

used

Number 

Work 

Tasks

Number 

Dispersed

Number 

Loaned

Number 

Work 

Tasks

Black Bear 0.2 0.2 - 1 0.6

Coyote 7 2 - 0.4 0.6

Gray Wolf 43 4 - 6 3

Red Fox 1 0.2 - - -

Moose 10 0.2 - - -

White-tailed Deer - - - 12 1

Total 61 7 - 19 5

Table A4. The annual average number of target birds hazed with balloons by WS in WDM 

activities from FY16-20 throughout the United States. 

Species Number 

used

Number 

Work 

Tasks

Number 

Dispersed

Number 

Loaned

Number 

Work 

Tasks

Double Crested Cormorant 10 0.6 - - -
23

Species Number 

used

Number 

Work 

Tasks

Number 

Dispersed

Number 

Loaned

Number 

Work 

Tasks

Mallard 0.2 0.2 20 - -

Canada Goose 0.6 0.2 - 9 5

Nene T&E 0.4 0.4 5 - -

Great Black-Backed Gull 1 1 - - -

Herring Gull 1 1 - - -

Laughing Gull 1 1 - - -

Ring-billed Gull 2 1 - - -

Broad-winged Hawk - - - 0.8 0.4

Red-tailed Hawk - - - 1 0.8

Osprey - - - 2 0.2

Rock Pigeon* - - - 0.2 0.2

House Sparrow - - - 0.2 0.2

Eastern Gray Squirrel - - - 0.3 0.2

Wild Turkey - - - 4 2

Vole - - - 0.3 0.2

Downy Woodpecker - - - 1 1

Hairy Woodpecker - - - 0.8 0.4

Pileated Woodpecker - - - 1 0.8

Red-bellied Woodpecker - - - 0.2 0.2

Yellow-bellied Sapsucker - - - 0.4 0.4

Sandhill Crane - - - 0.3 0.2

Total 16 5 25 22 12